Internal combustion engine



Oct. 11 1940. E. s. HALL INTERNAL COMBSTION ENGINE Filed Maron 27'l19:59

3 Sheets-Sheet l INVENTOR @MSM ` ct.- l, W40.

E. S. HALL INTERNAL COMBUSTI ON ENGINE :s sheets-sheet 2 'Filed March27, 1939 R O T. N 4 E V m MSM rOct. 1,1940. I E. s; HALL INTERNALCOMBUSTION ENGINE Filed March 27, 1959 3 Sheets-Sheet 3 INVENTOR atentedOct. l, 1940 UNITED STATES PATENT i'oFI-lcE 17 claims,

This invention relates to internal combustion engines and its salientobject is to provide a most compact engine of minimum bulk and weight.Compactness and minimum weight are best attained with those engine typeswhich have small crankcase volume, as for example, the radial eriginesin which the cylinders face each other around a common mechanism, or theopposed cylinder -engines or the barrel type engines in which similargroups of cylinders face each other with the engine mechanism betweenthem. This invention may be conveniently described as applied to thenormal barrel engine with cylinders parallel to the shaft intwoi-similar groups facing each other with the rotary-reciprocatingmechanlsm between them, but it is applicable also to other types ofengines such as those mentioned above.

An object of this inventionis to provide a shcrter and more compactparallel cylinder engine of less specic weight. and to provide -meansfor reducing the length and weight oi. 4such an engine by about 25%under what has been possible.

25 In a parallel'cylinder engine of the normal type, bearing loads aremuch lowerand other mechanical conditions much ,superior if the engineis run on the two-stroke cycle. For twostroke operation, uniflowscaverige is preferred, with intake ports at one en'd of the cylinderand exhaust ports at the other end. Thermal conditions in thepistons arebest if the pistons control the intake ports while the exhaust portsarelcon-V trolled by valves. An object of this invention is to provide auniflow two-stroke engine with irnproved sleeve valves and sleeve valveoperating means, at thesame time using the sleeve valves to permitshorter piston members than would otherwise be possible for a givenpiston stroke, thereby shortening the engine and reducing its weight.Another object is to reduce engine weight and size still more by usingthe sleeve valves as cylinder liners, dispensing with the" need of ilxedliners and separate valve systems. Another object is to provide thepiston members with oil contrpl rings which never pass over thepiston-controlled ports, and at the same time having shorter pistonmembers than would be possible, even without oil control rings, ifsleeve valves were not used. The foregoing objects are attained by usingsingle sleeve valves in a' twostroke parallel'cylinder engine, thesleeves having strokes longer than usual and timed almost in time withthe-piston strokes, softhat the'sleeves,fl

55 as they move outward from the cylinders, retain the piston rings inoperable position after the rings have passed beyond the mouths of thecylinders themselves, thereby permitting the piston members to be muchshorter, 'resulting in a shorter and lighter engine. the reductionamounting ordinarily to about 25%.

Another object is to provide sleeve valves for a parallel cylinderengine with driving means operably connecting the sleeves with therotary-reciprocating engine mechanism, whereby the l0 sleeve valves aregiven strokes somewhat shorter and preferably slightly advanced intiming relative to the strokes of the pistons.

Another :object is to provide sleevevalves which extendv thru bothcoaxial cylinders in a normal parallel cylinder engine, the sleevesserving not only as valves and liners for the cylinders, but ascrosshead guides for the piston members. A further object is to providemechanisms for driving such combined sleeve valve and crosshead guideunits.

Another object is4 to provide individual sleeve valves for the severalcylinders of a parallel cylinder engine, so that the port timing can besuited to each cylinder, with means for driving the sleeves from theengine shaft independently of the rotary-reciprocating engine mechanism.Another ob ject is to provide a cam mechanism for driving suchindividualsleeve valves so as to make possible giving each sleeve theoptimum movement relative to piston movement, for the best conditions ofport timing andwear. Another object is to provide improved cam drivingmechanisms -for sleeve valves.

In parallel cylinder engines of the wabbler type, where therotary-reciprocating mechanism comprises a wabbler mounted on bearingsin-V clined to the shaft. some means oi' restraining the rotation of thewabbler or of controlling its float is desirable. An object of thisinvention is 40 to provide means for driving sleeve valves directly fromthe wabbler which driving means will function also to control thewabbler float, preferably permitting the wabbler toA have its truegeometric motion. Another object is to provide means for eliminatingexcessive clearances in sleeve valve .operating mechanisms in a parallelcylinder engine.

In any. two-stroke engine. for best economy, fuel injection should beused. An object of this invention is-@to provide an improved fuelinjectionv system especially suited to a parallel cylinder engine.

'I'hese and other objects of the invention and 1 the means of attainingthem will be more clear from the following description in connectionwith the drawings in which g Fig. 1 is a longitudinal section of aparallel cylinder engine having a-wabbler mechanism and individualsingle sleeve valves, one in each cylinder, the valves being driven bycam mechanisms independent of the wabbler mechanism;

Fig. 2 is a radial or plan view, in section, of a reciprocating memberof the mechanism shown in Fig. 1;

Fig. 3 is a partial transverse section of the wabbler mechanism of Fig.1 taken thru the midsection of the reciprocating member of Fig. 2;

Fig. 4 is a longitudinal section of another parallel cylinder enginehaving a wabbler mechanism and tubular members each serving as sleevevalves for the cylinders of each pair and as a crosshead guide for thereciprocating piston member, these tubular members being driven directlyfrom the wabbler, and the driving mechanism serving also to control thewabbler float and maintain the geometrically correct movement of thewabbler;

Fig. 5 is a radial or plan view, in section, of one of the tubularmembers of Fig. 4, with the crosshead portion of the reciprocatingmember in in place A,

Fig. 6 is a transverse section thru the mechanism of Fig. 4, showingportions of the driving arrangements of the tubular members;

Fig. 7 is an alternate construction of the mechanism for driving thetubular valve and crosshead guide members directly fromthe wabbler whilemaintaining the wabbler oat;

Fig. 8 is a longitudinal section of a parallel cylinder-engine of. thcamtype, having a cam and roller rotary-reciprocating mechanism and sleevevalves, the latter being also crosshead f guides for the piston membersand cylinder liners,

driven by another cam mechanism; and Fig. 9 is a partial transversesection taken on the line 9-9 of Fig. 8.

Referring tongs. 1 3 of the draw1ngsshaft` is mounted in bearings and I2in cylinder blocks I3 and cylinderv covers I4 respectively. Casingmember I is interposed between and bolted to cylinder blocks I3. Formedin cylinder blocks I3 are cylinders I6 with their axes parallel to shaftI0. Shaft I0 ls axially located by slipper thrust bearing 20. Swashplate2| is fixed on shaft I0 in any suitable manner as by the splines andconical wedge pieces shown.

Wabbler 24, comprising two similar members bolted together.. is operablymounted with suitable bearings on `swashplate 2|. The two parts ofwabbler 24 are solids of revolution, their peripheral surfaces 26 and 26being cylindrical and the intervening surfaces 21 being plane.

Wabbler arm assemblies are spaced about wabbler 24, each assemblycomprising a pedestal member 29, cap 29, wristpin bushing 39, andCapscrews 3|, together with wristpin 32 locked in radial 33 by setscrews 34. Pedestal 23 has inner surfaces cylindrical and planeconforming respectively to cylindrical surfaces 25 and 26 and planesurfaces 21 of wabbler'A 24, and, as shown in Fig. 1, are bifurcated tostraddle the inner portions of the two members of wabbler 24 to assistin holding them together and for additional strength of the arm and itsattachment to the wabbler. Capscrews 3| clamp Wristpin bushing 30between cap 29 and pedestal member 28, holding them vsecurely to wabbler24. Bushing 30 is, free to rock and reciprocate on wristpin 32 asrequired by the operation of the mechanism, its axial movementibeingfinally y checked by the cushion action of loose tting dashpots 35formed in radial 33.

Radial 33 is operable in bore 36 in crosshead 31. Crosshead 31 visoperable in cylindrical bore I8 formed in casing member I5 coaxial withcylblocks I3 and are clamped to roller carriers |92 by screws |93.Rollers |95, integral with their pins, are operably mounted inhalf-journal bearings formed in roller carriers |92 and operably engagecam |94 which is xed on shaft I0.

Sleeve valves I9 are provided with intake ports 22 opening from the airchambers I3| in cylinder blocks I3 which are fed from suitable blowersor other means. Ports 22 are overrun and controlled by pistons l1. Thehead ends of sleeve valves I9 are bevelled internally to weaken themsufliciently so that they will expand under cylinder pressure tosealagainst leakage from combustion chambers |6| into exhaust ports 23.

Cylinders I6 in cylinder blocks I3 are closed by individual cylinderheads which form, with the heads of pistons |1, combustion chambers I6I.Fuel pumps |62 are arranged radially relative lto shaft I0 and aireoperated by cam v|64 which is xed on shaft I0. Each fuel pump |62 isinserted in' a bore in cylinder cover I4- and extends outward toward oneof the cylinder heads |60. Fuel nozzle |66 passes thru the body of fuelpump |62 and into cylinder head |60 with suitable packing nuts so thatfuel may be delivered directly from fuel pump |62 to nozzle |66 underhigh pressure without any piping.

Operation of the engine on the two-stroke compression ignition cycle iswell understood. Fuel injected thru nozzle |66 into the charge of air incombustion chamber |6| which charge has been heated by compression,ignites and the combustion drives the piston outward. Sleeve valves I9are timed to open exhaust ports 23 well in advance of the opening ofintake ports fore pistons I1 close intake ports 22, to permitsupercharging the cylinders to blower pressure. Reciprocation of thepiston members is accompanied by rotation of shaft I0 by the action ofthe .wabbler mechanism in a well-known manner. The construction ofwabbler 24 and associated parts is such that practically no .torquereaction can be imposed on the wabbler, the wabbler normally tending tofloat in the middle of its rotational freedom. Should wabbler 24 tend togo to the limit of its rotational freedom, dashpots 36 may serve ascushions of oil and air to prevent knocking. Rotation of shaft I0 alsocauses rotation of cams |94 which coact with vrollers |95 and associatedparts to drive sleeve valves I9. At the right of Fig. 1, both intakeoperating mechanism comprising slippers 54|' mounted in recesses 540 inWabbler 54 andv in control ring being retained altho drawnseveral inchesbeyond and out of the mouth of cylinder I6. At the right of Fig. 1, itmay be noted that this oil control ring never passes above ports 22.

Referring to Figs. 4-7 shaft 46 is mounted in bearings-4| and 42 incylinder blocks 43 and covers 44 respectively. Casing member 45 isinterposed `between and bolted to -cylinder blocks 43. Formed incylinder blocks 43 are cylinders .46 with their axes parallel to shaft-4||.

vfrom and are spaced about Wabbler 54, each assembly comprising apedestal member 5B, cap 59, wristpin bushing 69, and capscrews 6|, to-

gether with wristpln 62 carried by and locked` in radial 63. Pedestalmember 56 has inner surfaces cylindrical and plane conformingrespectively to cylindrical surfaces 55 and 56 and'plane surfaces 51 ofWabbler 54, and as shown in Fig. 4, are bifurcated to straddle the innerportions of the two members of Wabbler 54 to assist in holding themtogether, and for additional strength in the attachment of the Wabblerarm to wabbler 54. Capscrews 6| clamp wristpin bushing 60 between cap 59and pedestal member 58, holding them securely to Wabbler 54. Bushing6|)` crosshead 61. Pistons 4'| are vclamped to crosshead 61 by clamps 66and screws 69.

For each reciprocating member comprising two pistons 41 clamped to acrosshead 61, an integral tubular member 49 forms a sleeve valve andcyli inder liner for each 4piston'41 and a crosshead guide for crosshead51, the tubular member l49 being operable-in both opposite cylinders 46of cylinder blocksv 43. and extending from one to the other withincasing 45. Tubular members 49 are driven directly from Wabbler 54 bymeans of an cups in plungers 542 which plungers 542 are adjustablewithin bores in plungers 543, these latter plungers 543 beingreciprocable in bores in cylinder blocks 43 andhaving arms 449| operablyengaging tubular'members 49. to drive the same. Operating clearancesinthe operating mechanism connecting Wabbler 54 with tubular members 49are kept at a minimum by means of springs 544 and ball check valves 545cooperating with-oil pressure vfrom the engine lubrication systemsupplied thru suitable conduits 546 from main bearings 4|.

- In Fig. 7 an alternate design of the sleeve valve operatingmechanismtis shown. Plungers 543 with arms 49| are the same as thoseshown in Fig. 4, but inner plungers 642 are provided with offsetterminal discs 649 operably engaging4 sock- Vets 540 in Wabbler 54.During operation of the mechanism, plungers 642 and terminal discs 640rotate at the same speed asshaft 49.

Operation of the engine of Figs. 4-7 is similar to that of Figs. L-3.Tubularmembers 49 serve as sleeve valves, ascylinder liners, and ascrosshead guides for the piston members. With their operating mechanismsin .the intercylinder lead that of the piston members by twenty degreesof shaft rotation, and since the axes of 4plungers 542 and 543 are on acircle of substantially half` the radius of the cylinder pitch circle,the length of stroke of tubular members 49 is substantially half that ofthe piston members. Whenever the driving load is momentarily off fromone of the driving mechanisms comprising a slipper 54|, plunger 542 andplunger 543 and associated parts, spring 544 ac ts to elongate'tbevplunger' member 'taking up any clearance, oil

entering thru check valve 545 to .substantially maintain the new lengthof the plunger member under load, any excessive stress which mightresult being vrelieved by -slight leakage of oil trapped betweenplungers 542 and 543.

' Slippers 54| or offset terminal discs 540 could operate directly onthe plane outer faces of wabdispensing with the necessity for dashpotcushions 35 shown in Figs. 1-3. Slippers 54|, as they work around inrecesses 549, may rotate more or less in their cups in plungers 542;terminal discs 640 and their plungers 642 Vmust rotate in plungers 543as the Wabbler operates. If the Wabbler mechanism, were of any othertype than that shown, control means of this sort might be 'inadequatebecause the enginei torque reaction would 'be upon them, but with themechanism shown, the Wabbler control system must control only incidentaltendencies of the Wabbler to de part from its true motion, caused forthe most part by friction in the Wabbler bearings.

:isl

Referring to Figs. 8 and 9, shaft Bil-is mounted in bearings 8| and 62in cylinder blocks 63. Casing. member is interposed between and boltedto cylinder 4blocks 53. Formed in cylinder blocks 83 are cylinders 8 6with their axes parallel 15o-shaft 89; cylinders 84 formed in casingmember 85 are coaxial with cylinders 86 and of somewhat larger bore.

Tubular member 99 is operable withinv cylinders 64 and 86 as movablecylinder liners, crosshead guide; and sleeve valves for the pistonrmember comprising a pair of pistons 93 and connecting bridge portion.Cam member 81 is fixed on shaft 8|)` in any suitable manner and has apair of cams 88 and another pair of cams |l9., Cams 66 engage rollers 90integral with their pins to prevent rotation of the piston and sleevevalve members. A

Rollers 90 have their axes inclined for the double purpose of permittingthe rollers to reach inward to a cam of smaller diameter, thuspermitting a thicker and more rigid bridge portion for the pistonmembers and tubular members' 99, and of introducing an outward radialcomponent into the side thrust on the .piston members to avoid beamloading thereon, the resultant piston side thrust being towardamplebearing area of the bridge portion of the piston member and of thetubular member Where the latter bears in cylinder 84 in casing member95. The central or bridge portions of tubular members 99 are somewhatthicker than their sleeve valve portions. their exteriors conforming tothe respective bores of cylinders 8f3 and 86. Moreover, the central orbridge portions of tubular members 99 are cam ground externally, withinward reaching portions to provide mountings for the rollers 91.

Operation of an engine with the mechanism shown in Figs. 8 and 9 issimilar to that of the engine of Figs. 1-3. Piston thrust is convertedinto shaft rotation by the cam and roller mechanism instead of by awabbler mechanism, and similarly, tubular members 99 are driven by camand roller mechanism comprising cams 89 and rollers 9i.

An engine with the cam and roller mechanism is normally somewhat shorterand of less weight than an engine with the wabbler mechanism, but thereduction in engine length and weight resulting from the adoption ofsleeve valves having unusually long strokes timed substantially with thepiston strokes, is proportionally about the same. In a specific design,the length of the engine was reduced from 66" to 48", about 27%, and thereduction lin weight resulting from this reduction in length togetherwith the use of the sleeve valves as cylinder liners and the eliminationof any puppet or rotary valvev mechanism, was estimated at approximately33%. These reductions assist materially in the attainment of two-strokeaircraft Diesel engines of less specic weight than that of presentgasoline aircraft engines.

Having thus described the invention, it is obvious that the objectsthereof as set forth herein have all been attained. While specificembodiments of the invention have been shown and described, it isunderstood that changes may be made in the arrangement and in theconstruction of the various parts without departing from the spirit orscope of the invention as expressed in the following claims.

I claim:

1. In an engine comprising a shaft, cylinders spaced about and parallelthereto, pistons and piston sealing means operable therewith,.and meansoperably connecting said pistons with said shaft: means for retainingsaid sealing means in operable position when withdrawn beyond the mouthsof said cylinders and permitting said pistons (and therefore saidengine) to be shorter and of less weight thanwould otherwise bepossible, said means comprising sleeve valve members serving as cylinderliners and surroundingl .said pistons and sealing means, andreciprocable with telescopic effect on strokes shorter than, but

as frequent as and timed substantially with theV strokes of saidpistons.

2. An engine comprising a shaft, cylinders spaced about and parallelthereto, sleeve valve members operable in said cylinders, pistons andpiston rings operable within said sleeve valve members, mechanismoperably connecting saidI pistons with said shaft whereby Athe strokesof said pistons accompany rotation of' said shaft, and means forreciprocating said sleeve valve members with strokes shorter than, butas frequent as and timed substantially with the strokes of said pistonsretaining said piston rings in operable position within said sleevevalve members, even when said rings are withdrawn beyond the mouths ofsaid cylinders, permitting said pistons (and therefore said engine) tobe shorter and of less weight than would otherwise be possible.

3. A uniiiow two-stroke internal combustion engine comprising a shaft,cylinders spaced about and parallel thereto, cylinder heads closing theouter ends of said cylinders, sleeve valve'` members operable in saidcylinders, pistons operable within said sleeve valve members, mechanismoperably connecting said pistons with said shaft, intake ports in saidsleeve valve members and controlled by said pistons, exhaust passagesadjacent said cylinder heads and controlled by said sleeve valvemembers, and means for reciprocating said sleeve valve members onstrokes shorter than, but as frequent as and timed substantially withthe strokes of said pistons.

4. An engine comprising a shaft, cylinders spaced about and parallelthereto, sleeve valve members operable in said cylinders, pistonsoperable within said sleeve valve members, and a mechanism for theinterconversion of reciprocation and rotation operably connecting bothsaid pistons and said sleeve valve members with said shaft, the strokesof said sleeve valve members being shorter than, but as frequent as andtimed substantially with the strokes of said pistons.

5. An engine comprising a shaft, cylinders spaced about and parallelthereto, sleeve valve members operable in said cylinders,pistonsoperable within said sleeve valve members, a Wabbler mechanismoperably connecting said pistons with said shaft, and means operablyconnecting said wabbler mechanism with said sleeve valve' members fordriving them with strokes shorter than, but as frequent as and timedslightly in advance of the strokes of their respective pistons.

6. An engine comprising a shaft, cylinders spaced about and parallelthereto, an individual sleeve valve member operable in each of saidcylinders, pistons reciprocable within said sleeve valve members,mechanism operably connecting said pistons with said shaft, and meansindependent of said mechanism and operably connecting said sleeve valvemembers with said shaft for reciprocating said sleeve valve. memberswith strokes shorter than, but as frequent as and timed substantillywith the strokes of their respective pistons.

7. In an engine comprising a shaft and cylinders spaced about andparallel thereto, the combination of an individual sleeve valve memberoperable in each of said cylinders, pistons reciprocable within saidsleeve valve members, a wab-' bler operably connecting said pistons withsaid shaft, and means for driving said sleeve valve inders facing eachother: integral tubular members each serving as movable cylinder linersand sleeve valves for a pair of opposite cylinders and as a crossheadguide for the piston member operable within said pair of cylinders.

9. A two-stroke engine comprising a casing, a shaft operably mounted insaid casing, cylinders in two similar groups facing each other acrosssaid casing, sleeve valve members operable in'said cylinders,double-ended piston members each operable in a pair of correspondingcylinders of said groups; and mechanism for the interconversion ofreciprocatio and rotation operably connecting said piston members andsaid sleeve val/ve members with said shaft, the strokes of said sleevevalve members being shorter than, but as frequent as and timedsubstantially with the 2,216,342 y strokes of. said piston members,permitting said piston members to be shorter `and said engine I morecompact and of less weight than would bers with said shaft, the'strokes-bf said sleeve o substantially withthe strokes of said pistons,and means for eliminating excessive clearance from said drivingmechanism. i

valve members being shorter than, but as fre. quent as and timedsubstantially with the strokes of said piston members.

1l. An engine comprising a casing, a shaft operably mounted in saidcasing, cylinders spaced about vand `parallel with said shaft, sleevevalve members operable in saidvcylinders, pistons operable within saidsleeve valve members, a wabbler Y operably mounted on said shaft onbearings' inclined thereto, operable connections between saidwabbler andsaid pistons, and means comprising operable connections between saidwabblerand said sleeve valve members for driving saidsleeve valvemembers and for preventing rotation of said wabbler and for holding saidwabbler substantially to its true geometric motion.

12. vAri engine comprising a casing, a shaft op- `erably mounted in saidIcasing, cylinders spaced about and parallel with said shaft, sleevevalveV membersv operable in said cylinders, pistons reciprocable Withinsaid sleeve valve members,

.means operably connecting said pistons and said shaft, mechanismfor'driving saidr sleeve 'valve members on'strokes as frequent as andtimed 13; An engine comprising a casing, a shaft operably mounted inlsaid casing, cylinders spaced about and parallel with said shaft, sleevevalve members operable in said cylinders, pistons operable Within saidsleeve valve members, 4means. operably connecting said pistons andsaid'shaft,`

mechanism for driving said sleevelvalve'members from said shaft, andmeans for eliminating excessive clearance from said driving' mechanismand comprising a piston and cylinder,v a springV urging the pistonoutwardly from said cylinder,

and-a check valve for trapping oil withins'aid cylinder.

,14. In a parallel cylinder engine having a shaft and cylinders spacedabout and parallelthereto, a fuel supply' system comprising a cam onsaid shaft, fuel pump units radiallyvdisposed about and driven by saidcam and extending across the -heads of said cylinders.- and fuelinjection nozzles inserted thru said'fuelV pump units into said cylinderheads.

15. An engine comprising a casing,` bearings supported by said casing, ashaft operably mounted in said bearings, cylinders in two groupsfacving-each other across "saidcasing, sleeve valve members having portsand operable in said cylinders, piston members operable Within saidsleeve valve members, oil control rings on said piston members, andmechanism for the interconversion of reciprocation and rotation operablyconnecting said piston members and said sleeve valve members with saidshaft, the strokes of said sleeve valve members being asv frequent asand timed in advance but substantially with the strokes of said pistonmembers permitting said piston members to b e shorter than wouldotherwise be possible by the telescopic effect and preventing said oilcontrol rings Vfrom everpassing over said ports.

16. Anengine comprising' a shaft, cylinders spaced about and paralleltov said shaft, sleeve valves operable in said cylinders, pistonsoperable within said sleeve valves, and means` for reciprocating bothsaid pistons and said sleeve valves upon rotation of said shaft, thestrokes of said sleeve valves beingrshorter than, but as frequent as andtimed substantially with thecorrespond- Ying strokes of said pistons,said means comprising rollers operablyseated in said pistons and insaidV sleeve valves, and a cam member xed upon said shaft and operablyengaging all of said rollers. y I i 17. 'In an engine having a shaft, adouble-ended piston members operably connected to said shaft, and twosimilar groups of cylinders facing each other: integral tubular memberseach serving as movable cylinder liners and sleeve valves for a pair ofopposite cylinders, and as a crosshead guide for the piston .memberoperable within said pair of cylinders, and means for driving each ofsaid tubular members on strokes as frequent 4as and timed substantiallywith the strokes of the corresponding double-ended piston member.

` EDWIN S. HAH..

